A review and discussion of new knowledge on the structure and function of mammalian alkaline phosphatases (APs) gained over the last 25 years. It covers: * The structure, regulation and expression of the AP genes * The three-dimensional structure of APs and mutagenesis work that further defined the structural/functional domains of the isozymes * The phenotypic abnormalities of the different AP knockout mice * Our current understanding of the in vivo...